使用 lxml python 更新 xml 文件答案

【问题标题】：update xml file with lxml python使用 lxml python 更新 xml 文件
【发布时间】：2018-06-02 16:04:26
【问题描述】：

我有一个XML 文件，其中包含会议室可用性详细信息。我已经编写了应用程序来读取该 xml 文件并将信息存储到两个字典中，一个用于大会议室，另一个用于小会议室。我的任务是为请求的模式更新 xml 的“isMeetingRoomAvailable”参数。

例如：对于 TowerName = 第一塔，meetingRoomName = ABC 和 MeetingRoomTimeStamp = "2018-05-31 00:45:00"，我必须将 isMeetingRoomAvailable 值更新为 1。

下面是我写的sn-p：

from lxml import etree

root = etree.parse('test.xml')
bigRoomAvailabilityDict = {}
smallRoomAvailabilityDict = {}
towerNames =  root.xpath("/root/Towers/Tower/TowerName")
MeetingRoomNames = root.xpath("/root/Towers/Tower/MeetingRooms/BigMeetingRooms/MeetingRoom/MeetingRoomName")
for tower in root.xpath("/root/Towers/Tower"):
    towerName = tower.xpath("TowerName")[0].text
    for lr in tower.xpath("MeetingRooms/BigMeetingRooms/MeetingRoom"):
        meetingRoomName = lr.xpath("MeetingRoomName")[0].text
        MeetingRoomMailId = lr.xpath("MeetingRoomMailId")[0].text

        str = towerName + " " + meetingRoomName + " " + MeetingRoomMailId
        for timeAvai in lr.xpath("MeetingRoomAvailabilityInfo"):
            time = timeAvai.xpath("MeetingRoomTimeStamp")[0].text
            isAvai = timeAvai.xpath("isMeetingRoomAvailable")[0].text
            key = str + " " + time
            bigRoomAvailabilityDict[key] = isAvai

    for small in tower.xpath("MeetingRooms/SmallMeetingRooms/MeetingRoom"):
        meetingRoomName = small.xpath("MeetingRoomName")[0].text
        MeetingRoomMailId = small.xpath("MeetingRoomMailId")[0].text

        str = towerName + " " + meetingRoomName + " " + MeetingRoomMailId
        for timeAvai in small.xpath("MeetingRoomAvailabilityInfo"):
            time = timeAvai.xpath("MeetingRoomTimeStamp")[0].text
            isAvai = timeAvai.xpath("isMeetingRoomAvailable")[0].text
            key = str + " " + time
            smallRoomAvailabilityDict[key] = isAvai
def updateXML(towerName, meetinRoomName, timeStampVal):
    roomsFromXml = root.xpath("/root/Towers/Tower/MeetingRooms/BigMeetingRooms/MeetingRoom")
    # print(roomsFromXml)
    for index in roomsFromXml:
        roomNames = index.xpath("MeetingRoomName")
        for rooms in roomNames:
            # print(rooms.text)
            if rooms.text == meetinRoomName:
                allTimeStamps = index.xpath("MeetingRoomAvailabilityInfo")
                for timeStamps in allTimeStamps:
                    counter = 0
                    for myTime in timeStamps.xpath("MeetingRoomTimeStamp"):
                        counter += 1
                        if myTime.text == timeStampVal:
                            break
                    for isAvai in timeStamps.xpath("isMeetingRoomAvailable"):
                        counter -= 1
                        if counter == 0:
                            isAvai.text = 1

# for key, value in bigRoomAvailabilityDict.items():
#     print(key, "  " , value)

来自链接的 XML 文件...

<root>
  <Towers>
    <Tower>
      <TowerName>Tower one</TowerName>
      <MeetingRooms>
        <BigMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>ABC</MeetingRoomName>
            <MeetingRoomMailId>mail_id_ABC</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 05:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
          <MeetingRoom>
            <MeetingRoomName>JKL</MeetingRoomName>
            <MeetingRoomMailId>mail_id_JKL</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 05:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </BigMeetingRooms>
        <SmallMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>XYZ</MeetingRoomName>
            <MeetingRoomMailId>mail_id_XYZ</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 02:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 03:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:15:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:30:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 04:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 05:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </SmallMeetingRooms>
      </MeetingRooms>
    </Tower>
  </Towers>
</root>

【问题讨论】：

“请求的模式”从何而来？我没有看到 bigRoomAvailabilityDict 和 smallRoomAvailabilityDict 与 updateXML 函数（在你的 sn-p 中没有调用）有什么关系。
我已根据要求将 xml 文件存储的数据读入 bigRoomAvailabilityDict 和 smallRoomAvailabilityDict 字典，后来我使用这两个字典作为参考，现在我必须更新 xml 文件。我已完成读取 xml 文件并检查逻辑也已完成，但我一直在更新 xml 文件。

标签： xml python-3.x lxml

【解决方案1】：

如果我们只专注于更新 XML，我会做的是将树作为参数传递并传递包含其他值的 dict。

您可以在 xpath 谓词中使用这些值来缩小要更新的元素的范围。这应该比使用 for 循环来测试元素值要简单得多。

示例...

问题的参数（将 tower one 更改为 Tower one 以匹配 XML）

例如：对于 TowerName = Tower one，meetingRoomName = ABC 和对于 MeetingRoomTimeStamp = "2018-05-31 00:45:00"，我必须更新 isMeetingRoomAvailable 值为 1。

XML Input (test.xml)（修改为比原来的小）

<root>
  <Towers>
    <Tower>
      <TowerName>Tower one</TowerName>
      <MeetingRooms>
        <BigMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>ABC</MeetingRoomName>
            <MeetingRoomMailId>mail_id_ABC</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
          <MeetingRoom>
            <MeetingRoomName>JKL</MeetingRoomName>
            <MeetingRoomMailId>mail_id_JKL</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </BigMeetingRooms>
        <SmallMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>XYZ</MeetingRoomName>
            <MeetingRoomMailId>mail_id_XYZ</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </SmallMeetingRooms>
      </MeetingRooms>
    </Tower>
  </Towers>
</root>

Python 3.6

from lxml import etree
import sys

tower_name = "Tower one"
meeting_room = "ABC"
timestamp = "2018-05-31 00:45:00"


def update_xml(to_update, params):
    try:
        node = to_update.xpath("/root/Towers/Tower[TowerName='{}']/MeetingRooms/*/"
                               "MeetingRoom[MeetingRoomName='{}']/"
                               "MeetingRoomAvailabilityInfo[MeetingRoomTimeStamp='{}']/isMeetingRoomAvailable"
                               .format(params.get("TowerName"), params.get("MeetingRoom"), params.get("timestamp")))[0]
    except IndexError:
        sys.exit("cant find the xpath to update")
    else:
        node.text = "1"


tree = etree.parse("test.xml")
update_xml(tree, {"TowerName": tower_name, "MeetingRoom": meeting_room, "timestamp": timestamp})

print(etree.tostring(tree, encoding="unicode", pretty_print=True))

输出（来自印刷品）

<root>
  <Towers>
    <Tower>
      <TowerName>Tower one</TowerName>
      <MeetingRooms>
        <BigMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>ABC</MeetingRoomName>
            <MeetingRoomMailId>mail_id_ABC</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:45:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>1</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 01:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
          <MeetingRoom>
            <MeetingRoomName>JKL</MeetingRoomName>
            <MeetingRoomMailId>mail_id_JKL</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </BigMeetingRooms>
        <SmallMeetingRooms>
          <MeetingRoom>
            <MeetingRoomName>XYZ</MeetingRoomName>
            <MeetingRoomMailId>mail_id_XYZ</MeetingRoomMailId>
            <MeetingRoomAvailabilityInfo>
              <MeetingRoomTimeStamp>2018-05-31 00:00:00</MeetingRoomTimeStamp>
              <isMeetingRoomAvailable>0</isMeetingRoomAvailable>
            </MeetingRoomAvailabilityInfo>
          </MeetingRoom>
        </SmallMeetingRooms>
      </MeetingRooms>
    </Tower>
  </Towers>
</root>

【讨论】：